ARF1 controls proliferation of breast cancer cells by regulating the retinoblastoma protein.

The ADP-ribosylation factors (ARFs) 1 and 6 are small GTP-binding proteins, highly expressed and activated in several breast cancer cell lines and are associated with enhanced migration and invasiveness. In this study, we report that ARF1 has a critical role in cell proliferation. Depletion of this GTPase or expression of a dominant negative form, which both resulted in diminished ARF1 activity, led to sustained cell-growth arrest. This cellular response was associated with the induction of senescent markers in highly invasive breast cancer cells as well as in control mammary epithelial cells by a mechanism regulating retinoblastoma protein (pRB) function. When examining the role of ARF1, we found that this GTPase was highly activated in normal proliferative conditions, and that a limited amount could be found in the nucleus, associated with the chromatin of MDA-MB-231 cells. However, when cells were arrested in the G(0)/G(1) phase or transfected with a dominant negative form of ARF1, the total level of activated ARF1 was markedly reduced and the GTPase significantly enriched in the chromatin. Using biochemical approaches, we demonstrated that the GDP-bound form of ARF1 directly interacted with pRB, but not other members of this family of proteins. In addition, depletion of ARF1 or expression of ARF1T(31)N resulted in the constitutive association of pRB and E2F1, thereby stabilizing the interaction of E2F1 as well as pRB at endogenous sites of target gene promoters, preventing expression of E2F target genes, such as cyclin D1, Mcm6 and E2F1, important for cell-cycle progression. These novel findings provide direct physiological and molecular evidence for the role of ARF1 in controlling cell proliferation, dependent on its ability to regulate pRB/E2F1 activity and gene expression for enhanced proliferation and breast cancer progression.

Relationship between the percentage of predicted cardiorespiratory fitness and cardiovascular disease risk factors in premenopausal women: a MONET study.

OBJECTIVE: To determine the relationships between the percentage predicted cardiorespiratory fitness (%CRF) and the anthropometric and metabolic cardiovascular disease risk factors in asymptomatic, premenopausal women. METHODS: Data are baseline values obtained in 97 healthy premenopausal women (age 49.9 +/- 1.9 years; body mass index 23.2 +/- 2.2 kg/m(2)) participating in a longitudinal study from 2004 to 2009. The outcome measures were peak oxygen consumption (VO(2) peak), body mass index, body composition (percentage fat, fat mass, fat-free mass), waist circumference, abdominal subcutaneous fat, visceral fat, resting blood pressure and fasting lipids, glucose and insulin levels. RESULTS: The %CRF was negatively associated with body mass index, fat mass, percentage fat, waist circumference, abdominal subcutaneous fat, visceral fat, triglycerides, triglyceride/high density lipoprotein cholesterol, total cholesterol, total cholesterol/high density lipoprotein cholesterol, fasting insulin levels and HOMA-IR (- 0.59 < or = r < or = - 0.20; 0.01 < p < 0.05) and positively associated with insulin sensitivity index (r = 0.23; p < 0.05). VO(2) peak was associated with the same variables; however, correlations were slightly better (- 0.70 < or = r < or = 0.30; 0.01 < p < 0.05). Stepwise multiple regression analysis showed that %CRF was only independently correlated with plasma triglyceride levels. CONCLUSION: The results of this study suggest that %CRF was not a major predictor of anthropometric and metabolic variables associated with an increased risk of cardiovascular disease in asymptomatic premenopausal women. Finally, the VO(2) peak is a better predictor than the %CRF to assess the risk of cardiovascular disease in asymptomatic premenopausal women.

Alterations in the course of and histopathologic response to influenza virus infections produced by enflurane, halothane, and diethyl ether anesthesia in ferrets.

Alterations in the course of and histopathologic response to influenza viral infections by halothane, enflurane, and diethyl ether anesthesia were evaluated in ferrets. There were no significant differences in the incidence and duration of lethargy, pyrexia, rhinorrhea, or sneezing in infected animals given one of the three anesthetic agents under investigation, compared with those receiving no anesthesia. There were no differences in lung pathology in infected animals given one of the three anesthetic agents, or no anesthesia, though histopathologic changes in the nasal turbinates were significantly greater in ferrets given enflurane. This study suggests that general anesthesia administered to ferrets infected with influenza virus carries minimal morbidity, although enflurane anesthesia was found to produce greater histopathologic changes than the other agents.

Certified occupational therapy assistants.

The intent of this article is to identify changes in our professional environment and address ways in which Certified Occupational Therapy Assistants can prepare for and adapt to change. The emphasis is on individual responsibility for growth and survival.

[Spontaneous and experimental infection of alpine marmots (Marmota marmota) by the North American woodchuck hepatitis virus (Marmota monax). Initial results]. / Infection spontanée et expérimentale de la marmotte alpine (Marmota marmota) par le virus de l'hépatite de la marmotte nord-américaine (Marmota monax). Premiers résultats.

Summer's discovery in 1978 of a DNA virus, very close to human Hepatitis B virus in a woodchuck population in the U.S.A. (Pennsylvania) was a confirmation of the first description made by Snyder at Penrose Research Laboratory (Philadelphia). It was the first animal model of human B hepatitis infection. The comparative study of morphological, ecological and ethological characteristics of the marmot (Marmota marmota) and the woodchuck (Marmota monax) enables an easy distinction between these two species. The natural infection of M. monax by the WHV shows that the woodchuck is a good model for human B hepatitis and should be extended to M. marmota. A sample of 24 marmots caught in the Alpes of Haute-Provence has not revealed any spontaneous infection in these animals by the woodchuck virus. The failure of experimental inoculation of the marmot (24 animals) with the WHV confirms the refractory status of this species (no viremia and very low and short serological response with or without an immunosuppressive treatment). These preliminary results require a confirmation in other animals of different age and geographical region and also by using more specific tests such as molecular hybridization, research on DNA polymerase and direct transfection trials.

In vivo response of air-filled balloon-tipped catheters to nitrous oxide.

Four balloon-guided pulmonary artery catheters from each of two manufacturers were placed in eight anesthetized dogs, and balloon volumes were measured at randomized time intervals from 1 to 30 min during (1) ventilation with 100% oxygen and (2) ventilation with 70% nitrous oxide in oxygen. Catheters from one manufacturer showed no increase in balloon volume in either condition. The balloon volumes of catheters from the second manufacturer increased up to 17% during ventilation with nitrous oxide. Balloons of these catheters required less inflation pressure than those from the first manufacturer. It was concluded that the effects of nitrous oxide on the balloon volumes of pulmonary artery catheters in vivo are of little clinical significance.